325 MHz spoke腔的二次电子倍增效应

采用CST软件的粒子工作室模块, 对spoke超导腔中可能发生的二次电子倍增效应进行了分析研究，并采用二次电子倍增效应发生后形成稳定状态时的粒子数增长率来表征其强度。模拟计算表明:该腔存在两处二次电子倍增效应，spoke柱两端的两点一阶倍增; spoke腔两端侧壁与中心圆筒交界处的单点一阶倍增;二次电子倍增在加速腔压为0.65 MV时的增长率最高，而腔压大于1 MV时，增长率均为负，即无倍增发生。

Multipacting of 325 MHz spoke cavity for accelerator driven sub-critical system

This paper discusses a method of calculating the growth rate of the secondary electron number after electron multipacting in the spoke superconductive cavity for Accelerator Driven sub-critical System(ADS) with CST Particle Studio. The result shows that there are two types of multipacting in the spoke cavity above: two-point one order multipacting on the top of the spoke pole and one-point one-order multipacting at the corner of the spoke cylinder face. The crest of the growth rate of multipacting is at the accelerator cavity voltage of 0.65 MV while there is no multipacting when the voltage is higher than 1 MV in the simulation. A comparison about the growth rate curve between two different secondary electron emission coefficients of niobium in the inner face of the cavity is also showed.